package metrics

import (
	"io"
	"net/http/httptest"
	"path/filepath"
	"strings"
	"testing"

	"github.com/david/knox/internal/db"
	"github.com/prometheus/client_golang/prometheus/testutil"
)

func tmpKdb(t *testing.T) *db.KnoxDB {
	t.Helper()
	k, err := db.Open(filepath.Join(t.TempDir(), "index.db"))
	if err != nil {
		t.Fatalf("open db: %v", err)
	}
	t.Cleanup(func() { k.Close() })
	return k
}

func seed(t *testing.T, k *db.KnoxDB, src string, n int) {
	t.Helper()
	for i := 0; i < n; i++ {
		_, _, err := k.RecordObservation(db.ObservationRecord{
			Fingerprint:     "fp-" + src + "-" + string(rune('a'+i)),
			SourceID:        src,
			SourcePath:      src,
			Project:         "test",
			ContentType:     "test",
			Title:           src,
			Summary:         "s",
			CreatedAt:       "2026-08-29T00:00:00Z",
			Confidence:      0.9,
			IngesterVersion: "itest/v1",
		})
		if err != nil {
			t.Fatalf("seed: %v", err)
		}
	}
}

func TestMetricsSnapshot(t *testing.T) {
	k := tmpKdb(t)
	seed(t, k, "git", 2)
	seed(t, k, "browser-history", 3)

	s, err := k.MetricsSnapshot()
	if err != nil {
		t.Fatalf("snapshot: %v", err)
	}
	if s.Observations != 5 {
		t.Errorf("observations = %d, want 5", s.Observations)
	}
	if s.BySource["git"] != 2 || s.BySource["browser-history"] != 3 {
		t.Errorf("by source = %v", s.BySource)
	}
	if s.KnowledgeVector[k.NodeID()] == 0 {
		t.Errorf("knowledge vector missing own node")
	}
	if s.ByOriginNode[k.NodeID()] != 5 {
		t.Errorf("by origin node = %v", s.ByOriginNode)
	}
}

func TestMetricsScrape(t *testing.T) {
	k := tmpKdb(t)
	seed(t, k, "git", 2)

	m := New(k, "testnode")
	h := m.Handler()

	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest("GET", "/metrics", nil))

	body, _ := io.ReadAll(rec.Body)
	out := string(body)
	for _, want := range []string{
		`knox_node_info{name="testnode"`,
		`knox_observations_total{source_id="git"} 2`,
		`knox_gossip_pulls_total 0`,
		"go_goroutines",
		"process_cpu_seconds_total",
	} {
		if !strings.Contains(out, want) {
			t.Errorf("scrape output missing %q", want)
		}
	}
}

func TestMetricsCounters(t *testing.T) {
	k := tmpKdb(t)
	m := New(k, "t")

	// Manually drive counters through the Metrics API.
	m.IncrementPull(3)
	m.IncrementPush(7)
	m.IncrementErrors()

	if got := testutil.ToFloat64(m.pullsTotal); got != 1 {
		t.Errorf("pullsTotal = %v, want 1", got)
	}
	if got := testutil.ToFloat64(m.obsPulledTotal); got != 3 {
		t.Errorf("obsPulled = %v, want 3", got)
	}
	if got := testutil.ToFloat64(m.obsPushedTotal); got != 7 {
		t.Errorf("obsPushed = %v, want 7", got)
	}
	if got := testutil.ToFloat64(m.errorsTotal); got != 1 {
		t.Errorf("errorsTotal = %v, want 1", got)
	}
}